The proposed work is part of an overall program in studying the biosynthesis, metabolism, and function of hydroxy fatty acid sophorosides found in the yeasts Candida bogoriensis and Torulopsis. The glucosyl transferases from C. bogoriensis that catalyze the synthesis of 13-sophorosyloxydocosanoic acid copurify and seem to be part of the same polypeptide chain, having a molecular weight of about 50,000. This enzyme will be compared to a similar one from Torulopsis. We will attempt to obtain sufficient purified enzyme to make antibodies, so that the activity of the mRNA for this enzyme can be assayed in an in vitro translation system. The level of glucose in the culture medium affects the production of this enzyme, and the total glycolipid. We will also investigate the effect of glucose on the production of the glycolipid aglycone, 13-hydroxydocosanoic acid.